1. Field of the Invention
The present invention relates to a power supply, and more particularly to a communication circuit of a power supply.
2. Description of the Related Art
Power supplies are used to provide a regulated power source to the electronic circuit such as computers, home appliances, etc. The power supply is also used for protecting the user from electric shock. The power supply thus becomes a significant unit that needs to be certified by safety requirements. Beside, the power supply will produce heat during the power conversion. Therefore, many products are developed to use an external power supply or a power adaptor to simplify the product design, such as notebook computers and a mobile phone charger, etc. However, the drawback of using the external power supply is lacking information of the power supply, such as the output voltage, output current and the operating temperature, etc., which causes the difficult for the power management and protections.